Coherin is a polypeptide complex isolated from the bovine neurohypophysis which has been shown to have a unique regulatory action on the small intestine of dog and man. This physiologic function has two phases. Coherin, when injected intravenously, immediately activates the inhibitory mechanisms in the small intestine producing a complete cessation of intestinal motility for periods lasting up to 40 minutes without loss of tone. This effect is dose-related, and can be achieved at a dosage measured in nanograms per kilograms of body weight. This physiologic property of coherin is a convenient basis for bioassay. The second phase of coherin activity follows the inhibitory phase and consists of a coupling of the electromotor performance of adjacent short segments of intestine, resulting in coherent motor patterns capable of propagating intraluminal contents in a caudad direction. In dogs that have been fasted more than 18 hours, it has been shown that the electromotor performance of adjacent short segments of intestine (3 cm in the jejunum, 0.6 cm in the ileum) is characterized by a lack of coordination or coupling. When the basic electrical rhythm (BER) and the mechanical events occurring in a segment of intestine are recorded, either by means of monopolar electrodes or by intraluminal pressure transducers, coordinated propagative activity can be identified. This can be done by measuring the time differential between events with multiple, equally spaced electrodes or balloons. Any mechanical or electrical activity that is propagated through the entire segment in the cauded direction can be identified by a constant time differential (phase lag) between electrical or muscular activity.
In this connection, attention is directed to the following publications:
1. Hiatt, R. B., Goodman, I., Sandler, B., Cheskin, H.: The effect of coherin on the basic electrical rhythm of the dog ileum in vivo. Am. J. Dig. Dis. 22 (2): 108, 1977; PA1 2. Mendel, C., Jaeck, D., Grenier, J. F., et al: Action of coherin on the basic electric rhythm and propagation in the isolated profused canine jejunum. J. Surg. Res. 19: 403, 1975; PA1 3. Hiatt, R. B., Goodman, I.: Peptide treatment of postgastrectomy obstruction. Arch. Surg. 111: 997, 1976; PA1 4. Hiatt, R. B., Goodman, I.: Long-term results in the treatment of regional ileitis with coherin. Am. J. Gastroenterol. 67: 274, 1977; PA1 5. Dauchel, J., Schang, J. C., Kachelhoffer, J., Eloy, R., Grenier, J. F.: Effects of some drugs on electrical activity of the gut in the postoperative period. Eur. Surg. Res. 8: 26, 1976. PA1 6. Goodman, I., Hiatt, R. B.: Coherin a new peptide of the bovine neurohypophysis with activity on gastrointestinal motility. Science 178: 419, 1972.
The isolation of this polypeptide complex has been described. See:
Because of the properties described above, the polypeptide coherin possesses useful activity on the smooth muscle of the gastrointestinal tract and other tissues. More particularly, it is useful in the treatment of ileitis, colitis, spastic constipation, spastic diarrhea, diverticulitis, peptic ulcer, post gastric surgery obstruction, and other conditions where irregularity of the smooth muscle function is involved.